Unlike their smiling cartoon brethren on television, real-life sea stars are suffering from a wasting disease epidemic in which they lose limbs and literally disintegrate in a matter of days. Photo: Kevin Lafferty/USGS.

Apart from SpongeBob’s pal Patrick, it’s hard to think of sea stars as living creatures. They’re sold in beachcombing shops as rock-hard, dried specimens for home décor, and artists use their symmetric shapes as motifs for ocean-inspired patterns. But sea stars are actually soft-bodied, colorful, mobile animals that hunt and feed on the ocean bottom, and since 2013, a mysterious disease has been killing them in droves along the U.S. and Canadian Pacific Coast—causing their arms to fall off and spilling their innards, and wasting away their bodies as if a heat gun were melting them from the inside.

The “Sea Star Wasting Disease” behind this deadly epidemic has been intensely studied by marine scientists in recent months, and now, a prime suspect has finally been identified as a probable cause of the disease.

Led by Cornell University microbiologist Ian Hewson with Cornell disease ecologist Drew Harvell, the study team comprises researchers from a who’s who of science institutions: Western Washington University, Wildlife Conservation Society, University of California-Davis, California Science Center, Los Angeles County Museum of Natural History, Monterey Bay Aquarium, National Parks Service, University of South Florida, USGS, University of California-Santa Cruz, Seattle Aquarium, University of Washington, University of Connecticut, and Vancouver Aquarium.

The sea star mortality was so sudden and unprecedented that biologists were unprepared and short on resources, says study coauthor Kevin Lafferty, a marine ecologist and parasite specialist with the USGS Western Ecological Research Center. “Lots of people were scrambling to learn what was going on. Ian started having interesting findings with densovirus, so he and Drew helped pull together a team of interested scientists to donate time to the effort.” The USGS Western Fisheries Research Center also provided aquarium space at their Marrowstone Laboratoryin the course of the research.

Sea star die-offs have been observed in past decades, but none were at this geographic scale. Since June 2013, Sea Star Wasting Disease cases have been reported from Baja California in Mexico, southern California, northern California, Oregon, and all the way to southern Alaska. Worse, as many as 20 sea star species have been affected.

“Because it’s happening underwater, this devastation may be difficult for many people to picture,” says Lafferty. “But imagine if all the songbirds from Alaska to Mexico started falling out of the sky, dropping their wings and disintegrating into a pile of feathers. You’d wonder if you were in an Old Testament-style plague.”

Scientists raced to find a cause, ranging from pollution to storm surge damage. But when Sea Star Wasting Disease began to hit an aquarium that used natural seawater from the ocean, new clues emerged.

The disease did not spread into tanks where incoming seawater was treated with ultraviolet light, but it did spread into tanks with untreated water—suggesting that a living pathogen was in play, instead of a chemical pollutant. Furthermore, trapping mechanisms like sand filters did not halt the disease spread from tank to tank, suggesting that the pathogen was microscopic and transferable by water, rather than only via direct contact between infected sea stars.

With that in mind, Cornell researchers devised a laboratory experiment using sunflower sea stars (Pycnopodia helianthoides) that showed symptoms of Sea Star Wasting Disease, removing tissue samples from these sick animals. The tissue was minced and blended in seawater, then passed through super-fine filters designed to remove bacteria but allow smaller materials—including viruses—to pass through.

This filtered blend was then injected into healthy sea stars, which all began to show wasting symptoms after two weeks. Researchers then took tissue from this set of newly diseased sea stars to create a second blend, injecting this into yet another group of healthy sea stars. Sure enough, these sea stars also showed wasting symptoms after two weeks.

Meanwhile, another group of healthy sea stars was subjected to the same experiment, but they were injected with a boiled version of the blend intended to destroy any biologically active material. None of these sea stars developed wasting symptoms, and the experiments proved that some sort of virus-sized, biologically active entity could trigger wasting symptoms in one sea star, and continue to infect others.

The sunflower sea star (Pycnopodium helianthoides) can be found in a variety of colors in the wild, like this healthy specimen with a lavender hue. Photo: Kevin Lafferty/USGS.

A simplified diagram of the Sea Star Wasting Disease experiment devised at Cornell University, used to prove that a virus-sized, biologically active entity was triggering wasting symptoms in sea stars. Graphic: Ben Young Landis/USGS, based on Hewson et al. 2014.

“We went back to these sick and healthy sea stars to filter and extract virus particles from their tissue, and sequenced the genomes of these virus particles to uncover the types of viruses present,” says Hewson, the Cornell microbiologist and the study’s senior author. “The sick animals had higher prevalence of one viral group, the densoviruses. We were able to assemble a near-complete viral genome from the sick sea stars—a densovirus genome new to scientific record—and gave it a name: ‘sea star associated densovirus,’ or SSaDV.”

But was SSaDV also related to wasting symptoms in sea stars in the wild? Drew Harvell, the marine disease specialist at Cornell, had been making field observations of the wasting disease and collected samples for the viral genome analysis. She rallied researchers at different institutions to gather tissue from more than 300 sick and healthy sea stars from the wild, across 14 different species. Kevin Lafferty at USGS then performed statistical analyses on the results. “We confirmed that wild sea stars were more likely to be diseased if they carried a high viral load of SSaDV,” says Lafferty.

Many-Armed Mystery

A video by Robert Beck of Brigham Young University and Benjamin Miner of Western Washington University showing the mysterious symptoms of the Sea Star Wasting Disease—including causing a sea star’s arm to walk away from its deteriorating body. Video: Western Washington University.

If SSaDV is indeed the culprit behind the current Sea Star Wasting Disease epidemic, that would leave researchers with even more mysteries. During the study, the team also analyzed preserved sea stars from past decades for viral traces, and found evidence of SSaDV or similar viruses in museum specimens dating back to the 1940s.

But if SSaDV has been in the wild around all this time, and appears to be a virus that can be freely transmitted in the water column and in sediments, why is it all of sudden a problem now?

“There’s a lot to untangle,” according to Lafferty, whose USGS research often examines the role of disease organisms in natural food webs and their usefulness as indicators of ecosystem function. “Parasites and pathogens are part of the natural food web, and just like wolves or sharks or any other organism, they can be affected by changes in the environment or their prey. So something has changed recently in Pacific waters—perhaps booms in sea star numbers, some stressor to sea star immune function, or some other environmental disturbance—to have set the stage for the current sea star wasting epidemic.”

How You Can Help: As the investigation continues, the public can still contribute citizen science data by reporting new cases of Sea Star Wasting Disease that they observe while diving or exploring tidepools. Look for instructions at this UC Santa Cruz website: www.seastarwasting.org.

Tidepool scenes of vibrantly colored sea stars could become a rarity as the Sea Star Wasting Disease spreads. When asked recently to take photos of sea stars along his home coast of Santa Barbara, California, USGS ecologist Kevin Lafferty responded: “There are no sea stars now to photograph.” Photo of Pisaster ochraceus sea stars in San Juan Islands, Washington: Kevin Lafferty/USGS.

#USGS#

]]>http://www.usgs.gov/blogs/features/usgs_top_story/virus-calculated-as-culprit-killing-sea-stars/feed/0Sea Star Succumbing to Sea Star Wasting DiseaseGiant Sea Star (Pisaster giganteus)Kevin LaffertySea Star Death from Sea Star Wasting DiseaseSunflower Sea Star (Pycnopodium helianthoides)Boiled Viruses from TissueA simplified diagram of the Sea Star Wasting Disease experiment devised at Cornell University, used to prove that a virus-sized, biologically active entity was triggering wasting symptoms in sea stars. Graphic: Ben Young Landis/USGS, based on Hewson et al. 2014.Purple Sea Star (Pisaster ochraceus)What We Leave Behindhttp://www.usgs.gov/blogs/features/usgs_top_story/what-we-leave-behind/
http://www.usgs.gov/blogs/features/usgs_top_story/what-we-leave-behind/#commentsMon, 28 Jul 2014 16:23:24 +0000anewmanhttp://www.usgs.gov/blogs/features/?post_type=usgs_top_story&p=200341Read more]]>When you go hunting or fishing, the gas in your car is unleaded but your ammo and tackle may not be. Even the most conscientious shooters and anglers may leave some of their ammo and tackle behind, and if it’s made with lead that could spell trouble for the birds that come along afterward.

There is copious scientific literature on the negative effects of lead from ammunition and tackle on wildlife. Nonetheless, the subject remains controversial among hunters and anglers. A team of scientists, led by USGS Wildlife Ecologist Susan Haig, recently published a new review of the literature on the subject. Their publication explores the effects of lead ammunition and fishing tackle on birds and investigates various measures to reduce their exposure to it. This information is critical to wildlife managers and outdoor enthusiasts who are trying to limit lead’s harmful impact on birds while also maintaining opportunities for hunting and fishing.

Why Lead?

An unfired and fired lead core bullet (with a copper alloy jacket) fired into a water barrel from a .30-06 rifle. Photo courtesy of Clinton Epps, Oregon State University.

Lead is the metal of choice in ammunition and tackle because of its low melting point and malleability, and its cost compared to alternative metals. In 2013 the USGS found that 69,000 metric tons of lead – that’s over 152 million pounds – were used to produce ammunition in the United States in one year. Annual estimates of lead fishing weights sold add almost another 9 million pounds. Together, that’s about one-and-a-half times the weight of the Titanic. Not all that lead ends up being left behind after every outdoor excursion, but some does.

According to Haig, birds ingest lead in different ways. Common Loons, for example, swallow lead sinkers and jigs, perhaps mistaking them for prey. Other birds eat lead pellets or fragments as grit to aid in digestion. Scavengers including condors and eagles often feed on carcasses of animals killed by hunters and subsequently ingest lead fragments. The impacts can range from lethargy and anorexia to reproductive issues and even death.

Start with Science

The review, published in the August issue of The Condor: Ornithological Applications, summarizes decades of research from the USGS and other institutions on the sources and effects of lead ammunition and fishing tackle on birds. It includes research on the physiological effects of lead eaten by birds, the wide range of lead poisoning responses by different bird species and the effects on population numbers.

The scientists also introduce three priority research directions to better understand the threat of lead poisoning on birds.

Better measurements of variation in sensitivity to lead exposure among bird species.

Better understanding of what areas are affected by sources of lead contamination in relation to bird exposure in those same locations.

Examination of the interactions between lead exposure in birds and other landscape-scale factors that affect bird populations.

Haig and her colleagues reviewed several different approaches to reduce birds’ exposure to lead from ammunition and fishing tackle.

Outreach is one approach. Haig says “Arizona Game and Fish joined with hunting groups to share information about the negative effects of lead on California Condors in the Kaibab Plateau region. One study estimated that over 80% of hunters switched to non-lead ammunition as a result, and no condors were found with lead poisoning the following year.”

Other approaches include regulations such as the Federal ban on lead ammunition for hunting waterfowl or state restrictions on the use of lead fishing tackle in certain areas. Successful approaches to reduce lead exposure in birds are most likely to come from wildlife professionals, hunters and anglers working together to sustain wildlife resources and society’s hunting and angling heritage.

“Fortunately,” Haig said, “there are some realistic and effective ways to decrease the danger of lead ammunition and tackle to birds and other wildlife.”

USGS Providing Sound Science

The USGS has long conducted research into the effects of contaminants on birds. The USGS Patuxent Wildlife Research Center, established in 1936, and the USGS National Wildlife Health Center, established in 1975, have been centers of expertise with enduring legacies in this field. The USGS Ecosystems and Environmental Health Mission Areas also support this research with many scientists across the country. The USGS is committed to helping Americans understand the impact lead poisoning has on wildlife. Communication among scientists, outdoor enthusiasts and policymakers will ultimately reduce the threat.

You can find out more information on contaminants and their effects on wildlife at the following USGS websites:

]]>http://www.usgs.gov/blogs/features/usgs_top_story/what-we-leave-behind/feed/0Lead Core Bullet SamplesBlack-billed MagpiesUnderstanding the Relation between Energy and the Environment using Integrated Sciencehttp://www.usgs.gov/blogs/features/usgs_top_story/understanding-the-relation-between-energy-and-the-environment-using-integrated-science-2/
http://www.usgs.gov/blogs/features/usgs_top_story/understanding-the-relation-between-energy-and-the-environment-using-integrated-science-2/#commentsWed, 04 Jun 2014 16:50:33 +0000anewmanhttp://www.usgs.gov/blogs/features/?post_type=usgs_top_story&p=197271Read more]]>Unlike a gas station, the Earth doesn’t have a convenient way of pumping natural resources buried underground. The Earth must be tapped, at a potential cost to the environment, to extract the oil and gas resources that were generated within organic-rich sedimentary layers millions of years ago. We have depended on fossil fuels heavily since the industrial revolution, which helped produce the quality of life we enjoy today. Even with the recent expansion of renewable energy, fossil fuels continue to fuel most of society’s increasing need for energy. This need to recover fossil fuels increases the probability of environmental implications related to their recovery. Society is challenged with balancing our need for energy with the desire to protect the environment and human health. Land managers in one geographic area, the Williston Basin, are currently balancing these needs and desires by using integrated scientific information to best manage their natural resources.

Oil well and a looming storm Preston/USGS.

Williston Basin

The roughly 135,000 square miles Williston Basin, a sedimentary basin located in the north-central United States and south-central Canada, has been a leading source for domestic oil and gas production for more than 50 years. This large region is roughly 30 percent larger than all of France. Today this region, which includes the well-known oil-producing Bakken and Three Forks Formations, is in the midst of a modern energy boom, driven by advances in oil and gas recovery technologies.

A portion of the Williston Basin is overlain by the Prairie Pothole Region, which is made up of hundreds of thousands of acres containing hundreds of thousands of wetlands, providing critical breeding and nesting habitats for a majority of North America’s migratory waterfowl, as well as habitat for other wildlife. Government and private land managers say it is a challenge to protect these critical habitats in the midst of this modern energy boom.

Due to the enormously complex and widely varied scientific needs coupled with the massive time and geographic scale, the U.S. Geological Survey is in a unique position to help our Nation understand the effects of current and historical oil and gas extraction on natural resources such as water supplies, plants, animals, and ecosystems as a whole. To better understand the issues associated with the Williston Basin, the USGS has assembled a team that spans multiple science disciplines to study and provide information that can help industry and resource managers make informed decisions about possible environmental effects from resource extraction.

Northern Leopard Frog (Rana pipiens). Photographer: Smith/USGS

One of the many ways USGS is employing this diverse yet detailed expertise is in the form of the Science Team about Energy and Prairie Pothole Environments (STEPPE) which is a coordinated group of USGS hydrologists, biologists, geologists, geophysicists, geographers and geochemists that are characterizing natural resources and applying the best available science to identify areas most at risk to contamination.

Brine pit in Sheridan County, Montana. Photographer: Nelson/USFWS

The contamination that the scientists are studying comes from saline water, a byproduct of oil and gas extraction. The team is also assessing the spatial relations between past and current oil well development and aquatic resources, the potential ecological impacts in the Williston Basin, and refining methods for detecting contamination in surface-water and shallow groundwater.

Understanding extraction effects

In a recently released report, the USGS STEPPE describes the potential environmental effects associated with past and current oil and gas production in the Williston Basin. A common issue in the basin is the produced water that includes naturally occurring brine, a fluid that is saltier than seawater and may be produced in large volumes when extracting crude oil. Produced water has contaminated groundwater, streams, and wetlands in areas of the Williston Basin.

This graphic shows the proximity of oil and natural gas wells to wetlands in a 36 sq. mile area of Burke County, North Dakota. This township contains some of the highest density of aquatic resources and extensive oil and gas development in the Williston Basin. Creator: Tara Chesley-Preston/USGS

A regional characterization of oil and gas wells and natural resources shows that about one-third of all wetlands in the Williston Basin portion of the Prairie Pothole Region are located within 1 mile of oil and gas wells, highlighting the potential vulnerability of these aquatic resources to brine contamination.

This is important because brine contamination associated with historical oil and gas production from several decades ago during a previous energy boom can and does migrate in shallow groundwater and surface water. The USGS STEPPE team has demonstrated that contamination can persist for at least four to five decades. The team confirmed that a combination of geophysical survey methods and water-quality analyses is an effective way to assess brine contamination from oil and gas production to aquatic resources.

The team continues its research and has identified that there are still significant information and data gaps related to potential environmental impacts of oil and gas production.

USGS STEPPE scientists are systematically researching the major issues that will help communities and land managers make informed decisions regarding areas most vulnerable to potential contamination associated with extraction activities, as well as providing crucial data about the effects those activities have on the environment. While hosting discussions and a multi-day workshop with resource managers, STEPPE scientists have also used decision support tools to show that research could be integrated with manager needs. With data from this study, communities can make informed decisions on land use and future conservation efforts.

The following information is a sampling of current USGS studies in the Williston Basin

Geophysical and geochemical methods can be used to determine the extent and magnitude of brine contamination in the groundwater. These methods were used on the Fort Peck Indian Reservation in Montana to indicate where brine water, originating from storage-tank facilities, oil wells, brine-injection wells, pipelines, and reserve/drilling pits used during oil production in the area contributed to groundwater contamination. The shallow groundwater is the only available source of potable groundwater for about 3,000 residents in and near the East Poplar oil field. One of the brine plumes is currently being remediated and the scientific coordination for this effort was recognized with a 2008 Department of the Interior Environmental Achievement Award. Similar methods were used to show that plumes of brine-contaminated groundwater from oil field sites are migrating to wetlands in the Prairie Pothole Region.

Water availability for energy resource production.

The development of the Williston structural basin provides an opportunity to study the critical water-energy connection within a groundwater context. A framework for assessing the large volumes of water needed for today’s energy development in this basin is given in a USGS Factsheet. A Williston Basin groundwater availability study is part of the USGS Groundwater Resources Program to assess and quantify the availability of the Nation’s groundwater resources. Equally important to questions of water supply and demand in this basin is water usage related to petroleum development. The USGS Energy Resources Program is developing a framework to assess potential future needs, along with water production, associated with development of oil and gas resources nationwide. An early application of this methodology will be a study of Bakken and Three Forks development, and the resulting water demand estimates will be used to understand future development and its relation to groundwater availability.

Water-quality characterization.

In 2013, water samples were collected from 30 randomly-selected domestic wells in the Upper Fort Union Formation of Montana and North Dakota to assess groundwater quality in the context of oil and gas development. Results from this study will provide detailed understanding of current groundwater-quality conditions in the Upper Fort Union Formation and provide a basis for comparison with future water-quality studies.

Assessing the ecological effects of oil and gas production.

Contamination associated with oil and gas production has been identified in the Williston Basin, but there is very little information regarding the actual ecological effects of oilfield operations or brine contamination. To address this information gap, various studies are being conducted to investigate potential effects of habitat fragmentation, the spread of invasive plant species, and the effects of elevated chloride concentrations on aquatic plants and invertebrates.

Identifying areas with high potential for produced-water contamination to aquatic resources.

Vulnerability of aquatic resources is partially based on oilfield (age and density of oil wells) and hydrogeological (surficial geology, wetland area, and length of streams) characteristics. Scientists evaluated the performance of a vulnerability assessment method at ten study sites in eastern Sheridan County, Montana using a Contamination Index (CI) to identify brine contamination. Nineteen of the forty water samples collected had CI values indicating contamination. Additionally, CI values generally increased with increasing vulnerability assessment scores with this correlation being stronger for groundwater samples than surface water samples.

Although generally low in concentration, a study of mercury levels in fish in 21 Western national parks did find some locations where mercury concentrations exceeded health thresholds for potential impacts to fish, birds, and humans, according to U.S. Geological Survey (USGS) and National Park Service (NPS) researchers in a recent publication. This study, the first of its kind, detected mercury in all of the fish sampled, even from the more pristine areas of the parks.

What is mercury?

Mercury is a toxic, global contaminant that threatens ecosystem and human health. It’s a naturally occurring element and the only metal that occurs as a liquid at room temperature. Mercury is also used in industrial practices, mostly for the manufacture of industrial chemicals and for electrical and electronic applications.

The U.S. Environmental Protection Agency (EPA) sets standards for safe consumption of fish for human health in regard to mercury levels. In addition, EPA and the U.S. Food and Drug Administration have issued a joint advisory regarding recommended consumption of fish and shellfish due to mercury levels. More than 16 million lake acres and one million river miles are under fish consumption advisories due to mercury in the United States, and 81 percent of all fish consumption advisories issued by EPA are because of mercury contamination.

Where were these fish found?

More than 1400 fish were collected between 2008-2012 from hard to reach, high elevation lakes and streams in 21 national parks in the western U.S. and Alaska. Sixteen species were sampled, with a focus on sport fish such as brook trout, rainbow, cutthroat, and lake trout; as well as smaller prey fish eaten by birds and other wildlife.

How did the mercury get to these remote areas?

Spatial distribution of the 21 national parks sampled in this study. Size of circle represents percentage of total dataset.

Although there are natural sources of mercury, such as emissions from volcanoes, the majority of the mercury in these high elevation areas arrives from man-made sources such as coal-burning power plants, waste incinerators, oil and gas wells, and mining operations. The mercury can originate many miles from the national parks, as it travels through the atmosphere as tiny particles or gases. It then settles to the ground by falling in rain or snow, or landing on the ground as dust particles. In wetlands, atmospheric mercury can be transformed into methylmercury, a more dangerous form to living organisms.

Methylmercury levels can accumulate in animals over time and actually increase in concentration up the food chain, resulting in very high levels in larger animals. This process is known as bioaccumulation and happens when predators eat prey animals that already have mercury in them. The mercury in the prey animals is then stored in the tissues of the predator.

Some fish found to be dangerous to human and animal health

During their research, the scientists found that the mercury levels in fish varied greatly, both between parks and among sites within each park. In most parks, mercury concentrations in fish were moderate to low in comparison with similar fish species from other locations in the western United States. Mercury concentrations were below EPA’s fish tissue criterion for safe human consumption in 96 percent of the sport fish sampled.

Although risk of harm to humans and wildlife may be low in many locations, there are substantial concerns about the locations with high risk. This study identified areas where additional research is needed to better understand the risk to all national park units, and other remote landscapes or understudied environments.

Ultimately, advisories and related warnings consider both the risks and benefits of consuming fish. Future collaborations between research groups would map patterns of mercury across national parks in greater detail, supporting resource manager decisions to protect both national park visitors and the wildlife they come to see.

Electron micrograph of the cutthroat trout virus (CTV) showing the small, round virions of approximately 30 nanometers in diameter containing a single-stranded RNA genome. CTV, whose genome was first characterized by USGS researchers, is being used in research into the human virus Hepatitis E.

A fish virus characterized by USGS scientists in cutthroat trout in California is being used in early steps toward research that could save thousands of human lives, thanks to both its resemblance to and its key differences from the human virus Hepatitis E.

The fish virus, known as cutthroat trout virus (CTV), was first isolated in 1988 and later found to be widespread among salmonids in the western United States. USGS research biologists Jim Winton and William Batts and colleagues were the first to characterize the genome. They found that CTV closely resembled the virus that causes Hepatitis E, a potentially deadly emerging human disease that is particularly dangerous to pregnant women. Hepatitis E virus has proven exceptionally difficult to grow in cell cultures, in part because the cells of the human liver, which it infects, are difficult to maintain in the laboratory. The fish cells that CTV infects, however, are much easier to culture. Winton and Batts recognized the potential to use CTV to create persistently infected cultures with established fish cell lines that could be used to advance Hepatitis E research. The fact that CTV is found in spawning trout, they believed, might eventually yield insight into Hepatitis E’s more deadly course in pregnant women. CTV, in short, could provide medical researchers with a convenient surrogate virus and animal model that could be used to test potential drug therapies and vaccines.

A new paper in the journal Antiviral Research demonstrates that CTV can indeed provide a powerful tool for studying Hepatitis E. The paper, which Winton co-authored with a team from Belgium, reports the results of successful experiments testing antiviral compounds for their ability to inhibit the growth of CTV in fish cells, an important step forward for medical researchers looking to develop ways to treat and prevent Hepatitis E in humans. In addition to being an available cell culture system and an easy-to-use and inexpensive animal model, CTV has the added advantage that it poses no disease threat to researchers. CTV, like most fish viruses, cannot be transmitted to people. That makes working with the virus in a laboratory setting much safer and easier than working with Hepatitis E would be.

“It’s great when your initial curiosity about a virus from healthy fish turns out to have important biomedical applications for humans,” said Winton. “It really shows how hard it is to fully anticipate where basic scientific research might lead.”

Hepatitis E: An Emerging Disease Difficult to Study and to Treat

Female refugees from Sudan hurry through a downpour in Yusuf Batil refugee camp, Maban County, South Sudan, in August 2012. Overcrowding in camps can place refugees at risk for contracting certain diseases. UNHCR and its partners are working vigorously to prevent and treat cases of malaria and water-borne diseases, including Hepatitis E, at the camp. Photo copyright UNHCR/B. Sokol

Typically acquired from contaminated water or infected swine, Hepatitis E virus infects tens of thousands of people annually in Asia, Africa and South and Central America. While most infected people clear the virus from their systems without sustaining much damage, for reasons that are still unclear, the virus often causes full-blown hepatitis and liver failure during pregnancy. As a result, Hepatitis E is responsible for a high fatality rate among pregnant women. The World Health Organization estimates that 56,600 people die from Hepatitis E annually. The only drugs known to treat Hepatitis E require long treatment periods, cause severe side effects and are not safe to use during pregnancy. Thus there are significant gaps in both the understanding of the biology of Hepatitis E and in the search for safe, effective antiviral drugs.

Batts, Winton and their California colleagues first published their results in 2011. Soon after, they were contacted by researchers in Belgium who wanted to use CTV-infected fish cell lines to screen potential antiviral drugs for treating Hepatitis E. Results from initial tests showed that, just as Winton and Batts had hoped, CTV does indeed provide an important model to help learn more about the biology of Hepatitis E and to test potential treatments and vaccines. The paper published this month by the Belgian team and Winton in the journal Antiviral Research reports the results of experiments that tested several antiviral compounds for their ability to inhibit the growth of CTV in fish cells. It also reports effects of sex steroids on virus replication that provide clues into the basis of the increased mortality from Hepatitis E observed among pregnant women.

Karama Adija, 65, rests on the back of a donkey-drawn “ambulance,” waiting to be taken to the clinic operated by a UN High Commission on Refugees partner organization, the International Medical Corps, in Gendrassa refugee camp, Maban County, South Sudan, in August 2012. Overcrowding in camps can place refugees at risk for contracting certain diseases. UNHCR and its partners are working vigorously to prevent and treat cases of malaria and water-borne diseases, including Hepatitis E, at the camp. Photo copyright UNHCR/B. Sokol

In addition to screening potential antiviral drugs using CTV-infected cell cultures, scientists could experimentally infect captive fish with CTV to test potential vaccines in vivo. This will allow a whole-animal approach to the testing of potential therapies or vaccines that would be more relevant for human health than tests conducted on cell cultures. It may also allow further study of the virus’s basic biology, including its reaction to fluctuating hormone levels associated with spawning.

A car approaches a dust storm near Winslow, Arizona, in April 2011. In drought years, low vegetation cover and disturbance to soil surfaces leads to more dust storms.

Dust storms that rolled across the Arizona desert July 21-22, 2012, effectively blinded motorists, knocked out electricity for thousands of people and grounded airline flights.

The weekend storms, 50 miles wide and up to 10,000 feet high, were followed by additional storm warnings into the following week. Like the storms that passed through Phoenix in July and October 2011, they carried large quantities of airborne particulates and caused considerable property damage and potential harm to human health.

But what is causing these storms?

USGS and partner research shows that there are many causes of dust storms. Two contributing factors are low vegetation cover and disturbance to soil surfaces.

Vegetation contributes to ecological integrity. The presence of plants reduces soil erosion and dust storms, because it keeps the soil intact, reduces wind momentum, and traps moving soil particles (See Figure 1). In spaces between the plants, many undisturbed desert soils are naturally armored by hardened physical and biological crusts.

Low vegetation cover can especially be a problem in drought years in abandoned agricultural fields, which are generally dominated by annual plants. This means that the consequences of dust storms, including motor vehicle crashes, are high in a drought year and low in years with more precipitation (See Figure 2).

Figure 1: The presence of plants reduces soil erosion and dust storms because it keeps the soil intact, reduces wind momentum, and traps moving soil particles. Intact soil surfaces, which may include soil crusts, can also reduce the risk of dust storms.

Similarly, in places where land-use activities destroy or reduce soil crusts and weaken soil stability, experts know to assume higher dust storm activity than in places where soils are left undisturbed.

Future climate scenarios predict that drought conditions will worsen, and therefore more dust storms are likely.

Nevertheless, site restoration and reduced disturbance can mitigate some of the factors that promote dust emission. The USGS and land managers are working together to better understand the causes and sources of dust storm activity in the southwestern United States.

Figure 2: The number of motor vehicle crashes caused by dust storms in Arizona has generally been lower when the annual precipitation has been higher. In a changing climate, climate scenarios predict more drought, which will likely mean more dust storms. But site restoration and reduced disturbance can mitigate some factors that promote dust emissions.

]]>http://www.usgs.gov/blogs/features/usgs_top_story/dust-storms-roll-across-arizona-2/feed/0A car drives toward a dust stormSee caption:See caption:Wind Energy and Wildlife: Free USGS Public Lecture July 26http://www.usgs.gov/blogs/features/usgs_science_pick/wind-energy-and-wildlife-free-usgs-public-lecture-july-26/
http://www.usgs.gov/blogs/features/usgs_science_pick/wind-energy-and-wildlife-free-usgs-public-lecture-july-26/#commentsMon, 16 Jul 2012 10:08:31 +0000ademashttp://www.usgs.gov/blogs/features/?post_type=usgs_science_pick&p=174577Wind-power development in the United States is increasing at a growing rate, with proposals to provide 20 percent of the country’s total power by 2030. But high numbers of bird and bat carcasses at some wind farms have raised concerns about the environmental impacts of this rapidly expanding industry. The U.S. Geological Survey invites the public to our July Evening Public Lecture, where USGS researcher Manuela Huso will give a talk titled “Wind Energy and Wildlife.” She will discuss why simple counts of carcasses beneath wind turbines do not provide reliable fatality estimates and what tools USGS scientists are developing to accurately estimate wildlife fatalities and help identify options for monitoring and mitigation.

How do we ensure a future of clean water supply, abundant energy resources, and preparedness for and safety during natural hazard events, among other critical needs?

We start with science.

The USGS is focused on some of the most significant issues society faces. Our mission is to provide leaders, land and resource managers, and the public with the tools necessary to meet these challenges.

Now we need your help to ensure that our science is headed in the right direction. Based partly on feedback we received from the public last year, we have created draft strategies for each of our major areas of research.

To read and comment on the drafts, visit our Start with Science site. There you’ll also find background information on this effort, including the teams of scientists creating the draft strategies.

Nearly two years after the Deepwater Horizon oil spill, the meticulous, long-term efforts of scientists finally yielded the official results: namely, that the brown, wilted, dying corals found at the Mississippi Canyon lease block 294 were indeed damaged by a plume of oil from the spill.

For many, it seemed a foregone conclusion. Back in December 2010, when news of the damaged corals first came out, their proximity to the leaking Macondo well seemed to be a “smoking gun” in its own right. What else could brown gunk (flocculent matter, if you are a scientist) covering damaged corals seven miles from the Deepwater Horizon site be, if not oil from the spill?

Yet, to this team of scientists, it was worth taking a closer look at the evidence with two-dimensional gas chromatography, sediment cores, coral samples, and mosaic imagery. Why? Because so much was at stake.

In order to understand the damage in the deep, the scientists had to start by understanding what was down there to begin with.

To support that mission, enter USGS research benthic ecologist Dr. Amanda Demopoulos, who studies life on the sea floor to piece together what types of organisms typically live together in deep sea communities. Her work involves digging sediment cores from the bottom of the ocean and sorting through the many tiny forms of life found there.

In addition to deep sea coral ecosystems, Demopoulos studies communities in parts of the Gulf where oil naturally seeps up from the seafloor and is in fact a wellspring of life, not a source of damage. Chemosynthetic ecosystems – the ones where food webs are based on chemicals rather than sunlight – tend to have different forms of life, such as tubeworms.

Demopoulos was on the November 2010 research expedition which first discovered the damaged corals. Funded by the National Oceanographic and Atmospheric Administration and the agency now known as the Bureau of Ocean and Energy Management, the goal of that expedition was to gather the basic data needed to construct a scientific understanding of the various undersea ecosystems. It was part of a decades-long collaborative effort among federal and university scientists to explore deep sea ecosystems in an effort to provide sound baseline information for governance decisions about how to best balance natural resource use with protection. Demopoulos recalled watching the first images from the damaged site come in from remotely-operated vehicle.

“When we were watching the ROV video in the lab, I looked up at the video screen, and it looked starkly different from anything we’d ever seen before,” Demopoulos said. “The corals were all dark grey and lumped over, and it was clear these animals were not healthy. We’d seen dead coral, but this was so different, we immediately knew it was worth investigating further. When we got closer, there didn’t seem to be any secondary colonization, as we’d seen in the past on dead coral.”

The fact that no new animals — such as barnacles or hydroids — had begun to attach to and grow on the dead corals suggested the coral deaths had been recent, noted Demopoulos. This process, known as secondary colonization, is commonly observed on dead corals, but takes time to occur.

After the discovery of the damaged coral, Dr. Charles Fisher from the Pennsylvania State University led a follow-up expedition to more carefully investigate the damage itself, supported by a special National Science Foundation RAPID grant. Fisher worked with Dr. Helen White from Haverford College, Woods Hole Oceanographic Institute, Temple University, USGS and BOEM to assess the damage.

This push core shows discrete layers in a typical sediment sample. The light brown organic layer sits above a dark gray clay sediment. Most of the animals are found in the top layer of sediment. Image courtesy of, Lophelia II 2009: Deepwater Coral Expedition: Reefs, Rigs and Wrecks.

Demopoulos’ part in the overall effort to understand life in the deep ocean has been to understand what lives in the sediments of different types of environments, such as deep-sea corals and chemosynthetic communities. Some species may be generalists found in a variety of environments, while others will be unique to one type of habitat. Demopoulos also pieces together new information about how these tiny organisms are connected through food webs.

Without a baseline for understanding what is typical, Demopoulos would not be able to assess how those sediment dwellers were affected by the oil spill. Based on her expertise with sediment samples, Demopoulos helped design the best approach for assessing the corals at the Mississippi Canyon lease block 294 for the presence of oil and the extent of damage.

“The challenge we faced in this study was piecing together what happened from multiple lines of evidence, because no one was sitting on the sea floor when the plume went by. The corals were the only witness,” said Demopoulos, “We had to consider the proximity to the Deepwater Horizon site and the fact a deep-water plume had recently passed over the site, then closely examine the corals for tissue damage and signs of stress, such as the presence of mucus, and of course, the chemical signature of the oil. It was truly an interdisciplinary effort.”

Demopoulos pointed out that the cumulative knowledge about deep-sea communities from previous expeditions provided the baseline for scientifically assessing what they saw at the site. “This is but one site in the Gulf of Mexico,” she said, “but it has shown how important it was for us to have a frame of reference as to what a healthy deep-sea coral ecosystem looks like. We are still trying to understand the extent to which this is occurring elsewhere in the Gulf of Mexico.”

Top: A black-legged tick, also known as a deer tick, is the most common carrier for Lyme disease. Bottom: A microscopic image of the bacteria Borrelia burgdorferi, which causes Lyme disease

Lyme Disease: Once Bitten Twice Shy

Most everyone has found an unwelcome tick hitchhiking on a pants leg after a ramble through some brush or have felt one walking up the back of their neck after spending time in a wooded area. As a child you may have remembered your mother snatching a tick off your arm as its tiny legs held tight.

Ticks can be a nuisance and their bites can cause irritation. More importantly, ticks have the distinction of spreading the widest variety of disease producing agents that are harmful to humans.

Lyme disease is the most commonly reported tick-borne disease in the Northern Hemisphere and if left untreated infection can spread to the joints, the heart and even the nervous system.

Lyme Disease History

The disease was initially named after the town of Lyme, Conn.where a number of cases were first reported in 1975. The emergence of the disease infected ticks has been linked to changing land use patterns as forested areas were cleared for agriculture and the white-tailed deer population dwindled in the late 1800s in the north eastern United States. The black-legged tick, or “deer tick,” the principle vector, or carrier of Lyme disease, made a comeback with the return of forested habitat in mid-1900s and the risk of human infection increased.

Since the mid-1970s Lyme disease has spread throughout New England, the Mid-Atlantic and the northernMidwest with cases reported in nearly every state.

USGS Science and Lyme Disease

Although the black-legged tick can be found throughout the Eastern United States, scientists were baffled as to why the Lyme disease cases were not found in all the places where the ticks carrying it were found. The USGS has collaborated with several universities in a National Science Foundation funded study to better comprehend the ecological drivers for the geographic disparity in Lyme disease risk in the Eastern United States.

Data on tick-host relationships, seasonal tick biology, and tick genetics will be studied after they are collected in nine separate field sites around the United States. Dr. Howard Ginsberg, a USGS Research Ecologist with the Patuxent Wildlife Research Center, is a Principle Investigator with the project. He explains that the application of modeling tools will help to shed light on the ecological processes liable for the variation in Lyme disease cases and may help to predict how climate change could affect this risk. “Lyme disease is a major public health problem,” said Dr. Ginsberg “and the reasons for its geographical distribution are ecological. The knowledge to be gained from this project will help us better predict the future distribution of this disease, and lower the risk to human health.”

The goal of the study is to better understand how the relationships between ticks, their hosts, and environmental factors influence disease transmission, which can lead to improved tick control measures and public awareness on the regional variation in the risk of Lyme disease.

What are the Signs and Symptoms of Lyme Disease?

Lyme disease is the most commonly reported tick-borne disease in the Northern Hemisphere and if left untreated infection can spread to the joints, the heart and even the nervous system. Photo credit: Creative Commons.

According to the Centers for Disease Control and Prevention (CDC) symptoms of Lyme disease may present themselves within a few weeks of being bitten by an infected tick. Symptoms that require immediate health care evaluation include:

Chills or fever

Aches and pains including headache and muscle and joint pain

A bull’s-eye rash which begins at the site of the tick bite and may appear within 3-30 days and is usually circular and called erythema migrans or EM.

What Can Be Done to Help Prevent Lyme Disease?

Because ticks are most active in the warmer months, the CDC advices the following measures in tick season (April-September):

Lyme disease patients treated early with antibiotics normally recover quickly and completely. A small percentage of patients have lingering symptoms and may need to receive a prolonged course of antibiotics.

Your best defense is to avoid tick infested areas and be vigilant in looking for unwelcome hitchhikers.

]]>http://www.usgs.gov/blogs/features/usgs_top_story/lyme-disease-once-bitten-twice-shy/feed/0lyme_tickA black-legged tick, also known as a deer tick, is the most common carrier for Lyme disease.800px-Tiger_Leaping_Gorge_trail_24Lyme disease is the most commonly reported tick-borne disease in the Northern Hemisphere and if left untreated infection can spread to the joints, the heart and even the nervous system.